Steam generating and superheating surface



Aug. 17 1926.

w. E. DOWD, JR

STEAM GENERATING AND SUPERHEATING' SURFACE Filed March 26, 1924 2 Sheets-Sheet 1 avwewto'a Aug. 17,1926. 1 1,596,412

W. E. DOWD, JR

STEAM, GENERATING AND SUPERHEATING SURFACE Filed March 26, 1924 2 Sheets-Sheei 2 Patented Aug. 17, 1926. v

UNITED STATES PATENT OFFICE...

WYLLYS E. DOWD, JR., NEW YORK, N.

Y., ASSIGNOR '10 POWER SPECIALTY COM- PANY, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

STEAM GENERATING AND SUPERHEATING SURFACE.

Application filed larch 26, 1924. Serial No. 701,915.

My present invention consists in a novel arrangement of steam superheating elements and steam generating elements adapted to be incorporated in, or to form a lining for, the wall of the combustion chamber of a furnace from which the elements absorb heat by radiation.

The use of steam generating and superheating elements as a screen or lining for a combustion chamber wall absorbing heat from the combustion chamber is desirable on a*ccount\of the heat absorption efiiciency and capacity of the-elements, and the protection afforded against overheating and consequent destruction of the combustion chamber Wall. The use of steam generating and superheater surface thus disposed is especially important in the case of superheating steam surface because Qf,the high superheating effect which can be obtained with a small amount of such superheating surface, and the fact that the superheating effect thus obtained does not tend to increase with the boiler load, as is the case with ordinary superheaters heated Wholly or mainly by contact with heating gases after the latter have been partially cooled by contact with steam generating surface. When steam superheating elements are incorporated in, or placed in front of a combustion chamber wall in which a high temperature is maintained, there is a tendency to a warping or bending of the elements as a result of the temperature differences to which the front and back sides of the elements are subjected, and the fact that such elements must be provided with thick walls to insure proper strength and durability while obtaining the desired heat transfer. The use of a lining for a combustion chamber Wall formed of tubular water containing steam generating elements is restricted by the fact that, if the extent of surface provided by these elements is suflicient to adequately protect against overheating of the combustion chamber walls, their heat absorption undesirably lowers the combustion chamber temperature.

The general object of the present invention is to combinesteam generating and steam superheating elements in the walls of a combustion chamber so as to avoid an undesirably large heat absorption by either set of elements while utilizing the water heating elements to resist the tendency of the superheating elements to bend in planes transverse to their lengths. This I accomplish by arranging the steam superheating and water heatingelements side by side alternately with respect to one another, and by mechanically connecting the superheating elements to the water heating elements. With the side by side and alternating arrangement of the two sets of elements, each set of elements screens the elements of the other set against the absorption of radiant heat to a certain extent, and reduces the amount of radiant heat which said other set absorbs as compared with the amount of heat which would be absorbed by it if the screening elements were simply omittedi The various features of novelty which characterize my invention are pointed outwith partigularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, and the advantages possessed by it, reference should be had to the accompanying drawings and descriptive matter in which I have' illustrated and described a preferred embodiment of the invention.

Of the drawings:

Fig. 1 is a somewhat diagrammatic elevation ofa boiler furnace;

Fig. 2 is an elevation of a portionmofflthe heating surface lining for the combustion chamber of Fig. 1;

Fig. 3 is a partial section on the line 3-3 of Fig. 1;

Fig. 4 is a view taken similarl illustrating a modified construction;

to Fig. 2

Fig. 5 is a section of the line 55 of Fig. 4;

Fig. 6 is a view taken similarly to Fig. 2 illustrating a second modification;

Fig. 7 is a section on the line 77 of- Fig. 6;

Fig. 8 is a view taken similarly to Fig. 2 illustrating a third modification;

Fig. 9 is a section on the line 99 of Fig. 8; and

Fig. 10 is a partial section on the line 10-10 of Fig. 7.

Fig. 1 is a somewhat diagrammatic representation of a water tube boiler furnace of conventional type comprising a bank of water tubes B located above a combustion chamber A with thetu-bes B connected at their ends to headers B, the upper ends of the upper headers B being connected to a steam and water drum 0 by the usual horizontal circulating tubes D, while the upper ends of the lower headers B are connected to the drum C by elongated nipples E. Incorporated in the front wall of the combustion chamber A are steam generating elements F and superheater elements G. As shown, the steam generating elements F are in the form of tubes each having its body portion surrounded by a casing formed of block-like sections F of cast iron or the like. The end portions of each element F are out-turned, the lower out-turned ends being connected to a lower header F while the upper out-turned ends are connected to a header F The tubular elements F and the headers F and F are connected in the water circulating system of the boiler. As indicated in Fig. 1, the connections for this purpose comprise a down-comer pipe H at one side of the boiler connected to the corresponding end of the header F and conduits B located at the front corners of the boiler structure at opposite sides of the series of upper headers .BniEachnconduit B is connected at its lower end to the cor responding end of the header F and is connected at its upper end to the steam and water drum C by tubes D, which may be perature of the front or combustion chamber side of each element G over the temperature of the back side of the element existing under var ing conditions of operation. In the particu ar construction illustrated in Figs. 2 and 3, this result is obtained by forming the elements G with ribs G which extend parallel to the combustion chamber faces of the elements G at the rear sides of the latter, and are received in correspondingly shaped grooves or slots formed in the sides of the casing blocks F adjacent the rear faces of the latter. By thus interlocking the elements G and F in the manner described, the full strength of the latter is utilized in resisting the tendency of the elements G to warp and bend While at the same time the bodily longitudinal expansion and contraction of each of the elements G and F relative to its neighbors is permitted. In practice, the elements F may be stiffened and held against any tendency to how with the superheater elements by suitable connections to an external framework or supporting means, shown as comprising angle bars K. The out-turned end portions of the elements F and the transverse pipe connections G to the elements G provide the similar to and are alongside th ir l iflexibilitymeeded to accommodatefitheahodil ing tubes D.

The elements F are spaced apart, and in the space between each adjacent pair of elements F is located a superheater element G. Each superheater element G in the form shown is made of cast steel sections connected end to end. Each element G is connected at its lower end by a transverse pipe section G to the superheater outlet header G and is connected at its upper end by a similar transverse pi e section G to the superheater inlet hea er G The latter is connected at one or both ends of the boiler to the steam space-in the steam and water drum C by a corresponding steam pipe J.

As shown best in Figs. 2 and 3, the elements Gare generally rectangular in cross section with a steam passage therein which 1s rectangular in cross section and is elongated 1n a direction parallel to the length of the headers G and G The casing blocks F of the elements F are generally rectangular in cross section, and as shown, the elements F and G unite to form a smooth heat absorbing surface exposed to the interior of the combustion chamber. The arrangement of the elements F and G to provide a smooth heat absorbing surface facilitates the removal of furnace dust de ositing thereon, which may be accomplishe in any suitable manner.

The elements F and G are provided, in accordance with the present invention, with means whereby the elements F resist the tendency of the elements G to bend or warp as the result of the varying excess in tem-.

longitudinal expansion and contraction Ff the elements.

In addition to the support against bending afforded the elements G by the elements F, with which they are interlocked, the elements F absorb heat from the elements G and thereby advantageously reduce the total amount of heat absorption by the latter. The set of elements F, and the set of elements G each co-operate to reduce the heat absorbed by the other set from the combustion chamber, in comparison with the amount of heat which would be absorbed by the set of elements, if the other set of elements were omitted, since each of the elements screens the side of each adjacent element against radiant heat absorption. Each element F absorbs heat from the adjacent element G and correspondingly cools the latter owing to the fact that the elements G are hotter than the elements F.

The characteristic advantages of the apparatus shown in Figs. 1, 2, and 3 can be obtained with different and simpler constructions. For example, as shown in Fi 4: and 5, the steam generating elements A and the steam superheating elements GA may be each in the form of a bare tube with the elements GA supported against warping by the elements FA through metallic clamping parts L and LA disposed at intervals along the length of the tube elements and clamping the elements FA and GA together, each pair ofclamping blocks L and LA bein held to ther by means of a bolt F we ded to 0 corresponding element FA screen the elements GA against the absorp' tion of radiant heat as compared with 'the arrangements shown in Figs. 6 to 9 inclusive, in which the elements FA and GA are arranged with their axes in the same plane.

In Figs. 6 and 7 the elements FA and GA are each connected at intervals along their.

lengths to transversely extending supports M by means of bolt-like projections F welded to the rear or outer sides of the elements FA as in Figs. 4 and 5, and similar bolt-like projections G welded to the rear or outer sides of the elements GA. Advantageously, the openings in the elements M, receiving the ends of the projections G are slotted in a direction parallel to the length of the elements GA to accommodate th bodily longitudinal expansion and contraction of the elements GA with respect to the elements FA.

In the construction illustrated in Figs. 8 and 9 the elements FA and GA are arranged side by side, as in-Figs. 6 and 7, and

each element GA is supported againstwarp-' ing by means of transverse metalbars or blocks 0 distributed along the length of the elements and each formed with openings to receive one or more of each of the elements FA and GA. 7

While in accordance with the statutes, I have illustrated and described the best forms of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of the ap' paratus disclosed without departing from the spirit of my invention as set forth in the appended claims, and that certain features of my invention may sometimes be used with advantage without a corresponding use of other features. Y

Having now described my invention, what I regard as new and desire to secure by Letters Patent, is:

1. Steam generating and superheating apparatus comprising tubular Water heating elements and super-heating elements arranged alternately along the side of a combustion chamber and absorbing heat by radiation from the latter, and mechanical connections between the elements whereby the water heating elements assist in preventing warping of the steam superheating elements,

T and each element tends to reduce the heat absor tion by neighboring elements.

2. team generating and superheating apparatus comprising tubular water heating elements and superheating elements arranged alternately along the side of a combustion chamber and absorbing heat by radiation from the latter, the water heating elements and superheating elements being formed with longitudinally extendin shoulders which co-operate to prevent ben ing of one element relative to the other.

'Signedat New York city in the county of New York and State of New York this 24th day of March A. D. 1924.

WYLLYS E. DOWD, JR. 

